1. Technical Field
Example embodiments generally relate to an image processing device to embed supplemental data in image data, an image processing method employed in the image processing device, a program for causing a computer to execute the image processing method, and a recording medium storing the program.
2. Description of the Related Art
Recent improvements in image processing technique enable exact copies to be made of original documents that are indistinguishable from the originals. Consequently, in order to prevent illegal duplication of important documents such as paper money and securities, there is increasing demand for technology that may prohibit or prevent such precise duplication.
Various methods have been proposed to restrict duplication of the important documents, confidential documents, or the like. For example, one proposed method superimposes a dot pattern on image data that is read together with the image data. When the image data is read and a dot pattern identical to a pre-stored duplication prohibition pattern is detected from such read image data, it is determined that the read image data is prohibited from being duplicated.
In the above-described method, however, there is a problem in terms of the method of superimposing the dot pattern on the image data. Specifically, because the dot pattern indicating prohibition against duplication is superimposed on the entire area of the image data including content, the dot pattern is superimposed even on the content such as a document or a photograph as illustrated in FIG. 1, degrading visual quality of the content data included in the image data.